Prostate cancer in male BRCA1 and BRCA2 mutation carriers has a more aggressive phenotype

Germline Mutations in ATM and BRCA1/2 Distinguish Risk for Lethal and Indolent Prostate Cancer and are Associated with Early Age at Death

BACKGROUND

Germline mutations in BRCA1/2 and ATM have been associated with prostate cancer (PCa) risk.

OBJECTIVE

To directly assess whether germline mutations in these three genes distinguish lethal from indolent PCa and whether they confer any effect on age at death.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective case-case study of 313 patients who died of PCa and 486 patients with low-risk localized PCa of European, African, and Chinese descent. Germline DNA of each of the 799 patients was sequenced for these three genes.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Mutation carrier rates and their effect on lethal PCa were analyzed using the Fisher's exact test and Cox regression analysis, respectively.

RESULTS AND LIMITATIONS

The combined BRCA1/2 and ATM mutation carrier rate was significantly higher in lethal PCa patients (6.07%) than localized PCa patients (1.44%), p=0.0007. The rate also differed significantly among lethal PCa patients as a function of age at death (10.00%, 9.08%, 8.33%, 4.94%, and 2.97% in patients who died ≤ 60 yr, 61-65 yr, 66-70 yr, 71-75 yr, and over 75 yr, respectively, p=0.046) and time to death after diagnosis (12.26%, 4.76%, and 0.98% in patients who died ≤ 5 yr, 6-10 yr, and>10 yr after a PCa diagnosis, respectively, p=0.0006). Survival analysis in the entire cohort revealed mutation carriers remained an independent predictor of lethal PCa after adjusting for race and age, prostate-specific antigen, and Gleason score at the time of diagnosis (hazard ratio=2.13, 95% confidence interval: 1.24-3.66, p=0.004). A limitation of this study is that other DNA repair genes were not analyzed.

CONCLUSIONS

Mutation status of BRCA1/2 and ATM distinguishes risk for lethal and indolent PCa and is associated with earlier age at death and shorter survival time.

PATIENT SUMMARY

Prostate cancer patients with inherited mutations in BRCA1/2 and ATM are more likely to die of prostate cancer and do so at an earlier age.

Rare Variation in TET2 Is Associated with Clinically Relevant Prostate Carcinoma in African Americans

BACKGROUND

Common variants have been associated with prostate cancer risk. Unfortunately, few are reproducibly linked to aggressive disease, the phenotype of greatest clinical relevance. One possible explanation is that rare genetic variants underlie a significant proportion of the risk for aggressive disease.

METHOD

To identify such variants, we performed a two-stage approach using whole-exome sequencing followed by targeted sequencing of 800 genes in 652 aggressive prostate cancer patients and 752 disease-free controls in both African and European Americans. In each population, we tested rare variants for association using two gene-based aggregation tests. We established a study-wide significance threshold of 3.125 × 10-5 to correct for multiple testing.

RESULTS

TET2 in African Americans was associated with aggressive disease, with 24.4% of cases harboring a rare deleterious variant compared with 9.6% of controls (FET P = 1.84 × 10-5, OR = 3.0; SKAT-O P = 2.74 × 10-5). We report 8 additional genes with suggestive evidence of association, including the DNA repair genes PARP2 and MSH6 Finally, we observed an excess of rare truncation variants in 5 genes, including the DNA repair genes MSH6, BRCA1, and BRCA2 This adds to the growing body of evidence that DNA repair pathway defects may influence susceptibility to aggressive prostate cancer.

CONCLUSIONS

Our findings suggest that rare variants influence risk of clinically relevant prostate cancer and, if validated, could serve to identify men for screening, prophylaxis, and treatment.

IMPACT

This study provides evidence that rare variants in TET2 may help identify African American men at increased risk for clinically relevant prostate cancer. Cancer Epidemiol Biomarkers Prev; 25(11); 1456-63. ©2016 AACR.

Implications of High Rates of Metastatic Prostate Cancer in BRCA2 Mutation Carriers

BACKGROUND

Patients with germline BRCA2 gene mutations (BRCA2mut) have more aggressive prostate cancer. Analysis of all reported germline BRCA2mut prostate cancer cases allows better understanding of the clinicopathologic features and survival outcomes of these men.

METHODS

A systematic review was performed with the MEDLINE database to capture articles evaluating clinicopathologic characteristics of men with BRCA2mut associated prostate cancer. Inclusion criteria were at least five subjects, confirmation of BRCA2mut status, and data for at least 2 clinical parameters of disease. Meta-analysis was performed on outcomes data. Chi-squared tests were used to compare disease features among men undergoing formal versus ad hoc screening, as well as an age of diagnosis less than versus greater than 65 years. Rates of metastatic disease among BRCA2mut cases were compared to rates among non-carrier control subjects and the general population using the SEER database.

RESULTS

Twelve out of 289 studies met our inclusion criteria, representing 261 BRCA2mut men. Among carriers, the median age at diagnosis was 62 years and median PSA was 15 ng/dl with 95% of men having a PSA>3. Over 40% of BRCA2mut patients had T3/T4 disease and over 25% were metastatic at presentation. Survival was worse in BRCA2mut men with prostate cancer when compared to non-BRCA2mut subjects. BRCA2mut carriers had significantly higher rates of metastatic disease (18%) versus non-carrier controls (8%) and the SEER population (4%).

CONCLUSIONS

BRCA2mut carriers are more likely to have poor risk of prostate cancer at presentation and exhibit worse oncologic outcomes relative to non-carriers, including a fourfold increase in metastatic disease. Younger men and those undergoing formal screening present with less advanced disease which supports a need for earlier identification and screening protocols. Additionally, this population may benefit from alternative therapeutic paradigms. Prostate 76:1135-1145, 2016. © 2016 Wiley Periodicals, Inc.

Biallelic BRCA2 Mutations Shape the Somatic Mutational Landscape of Aggressive Prostate Tumors

To identify clinically important molecular subtypes of prostate cancer (PCa), we characterized the somatic landscape of aggressive tumors via deep, whole-genome sequencing. In our discovery set of ten tumor/normal subject pairs with Gleason scores of 8-10 at diagnosis, coordinated analysis of germline and somatic variants, including single-nucleotide variants, indels, and structural variants, revealed biallelic BRCA2 disruptions in a subset of samples. Compared to the other samples, the PCa BRCA2-deficient tumors exhibited a complex and highly specific mutation signature, featuring a 2.88-fold increased somatic mutation rate, depletion of context-specific C>T substitutions, and an enrichment for deletions, especially those longer than 10 bp. We next performed a BRCA2 deficiency-targeted reanalysis of 150 metastatic PCa tumors, and each of the 18 BRCA2-mutated samples recapitulated the BRCA2 deficiency-associated mutation signature, underscoring the potent influence of these lesions on somatic mutagenesis and tumor evolution. Among all 21 individuals with BRCA2-deficient tumors, only about half carried deleterious germline alleles. Importantly, the somatic mutation signature in tumors with one germline and one somatic risk allele was indistinguishable from those with purely somatic mutations. Our observations clearly demonstrate that BRCA2-disrupted tumors represent a unique and clinically relevant molecular subtype of aggressive PCa, highlighting both the promise and utility of this mutation signature as a prognostic and treatment-selection biomarker. Further, any test designed to leverage BRCA2 status as a biomarker for PCa must consider both germline and somatic mutations and all types of deleterious mutations.

NCCN Guidelines Insights: Prostate Cancer Early Detection, Version 2.2016

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Prostate Cancer Early Detection provide recommendations for prostate cancer screening in healthy men who have elected to participate in an early detection program. The NCCN Guidelines focus on minimizing unnecessary procedures and limiting the detection of indolent disease. These NCCN Guidelines Insights summarize the NCCN Prostate Cancer Early Detection Panel's most significant discussions for the 2016 guideline update, which included issues surrounding screening in high-risk populations (ie, African Americans, BRCA1/2 mutation carriers), approaches to refine patient selection for initial and repeat biopsies, and approaches to improve biopsy specificity.

Prostate cancer

Much progress has been made in research for prostate cancer in the past decade. There is now greater understanding for the genetic basis of familial prostate cancer with identification of rare but high-risk mutations (eg, BRCA2, HOXB13) and low-risk but common alleles (77 identified so far by genome-wide association studies) that could lead to targeted screening of patients at risk. This is especially important because screening for prostate cancer based on prostate-specific antigen remains controversial due to the high rate of overdiagnosis and unnecessary prostate biopsies, despite evidence that it reduces mortality. Classification of prostate cancer into distinct molecular subtypes, including mutually exclusive ETS-gene-fusion-positive and SPINK1-overexpressing, CHD1-loss cancers, could allow stratification of patients for different management strategies. Presently, men with localised disease can have very different prognoses and treatment options, ranging from observation alone through to radical surgery, with few good-quality randomised trials to inform on the best approach for an individual patient. The survival of patients with metastatic prostate cancer progressing on androgen-deprivation therapy (castration-resistant prostate cancer) has improved substantially. In addition to docetaxel, which has been used for more than a decade, in the past 4 years five new drugs have shown efficacy with improvements in overall survival leading to licensing for the treatment of metastatic castration-resistant prostate cancer. Because of this rapid change in the therapeutic landscape, no robust data exist to inform on the selection of patients for a specific treatment for castration-resistant prostate cancer or the best sequence of administration. Moreover, the high cost of the newer drugs limits their widespread use in several countries. Data from continuing clinical and translational research are urgently needed to improve, and, crucially, to personalise management.

Estimation of High-Dimensional Graphical Models Using Regularized Score Matching

Graphical models are widely used to model stochastic dependences among large collections of variables. We introduce a new method of estimating undirected conditional independence graphs based on the score matching loss, introduced by Hyvärinen (2005), and subsequently extended in Hyvärinen (2007). The regularized score matching method we propose applies to settings with continuous observations and allows for computationally efficient treatment of possibly non-Gaussian exponential family models. In the well-explored Gaussian setting, regularized score matching avoids issues of asymmetry that arise when applying the technique of neighborhood selection, and compared to existing methods that directly yield symmetric estimates, the score matching approach has the advantage that the considered loss is quadratic and gives piecewise linear solution paths under ℓ₁ regularization. Under suitable irrepresentability conditions, we show that ℓ₁-regularized score matching is consistent for graph estimation in sparse high-dimensional settings. Through numerical experiments and an application to RNAseq data, we confirm that regularized score matching achieves state-of-the-art performance in the Gaussian case and provides a valuable tool for computationally efficient estimation in non-Gaussian graphical models.

EN2 in Prostate Cancer

Despite extensive efforts to identify a clinically useful diagnostic biomarker in prostate cancer, no new test has been approved by regulatory authorities. As a result, this unmet need has shifted to biomarkers that additionally indicate presence or absence of "significant" disease. EN2 is a homeodomain-containing transcription factor secreted by prostate cancer into the urine and can be detected by enzyme-linked immunoassay. EN2 may be an ideal biomarker because normal prostate tissue and benign prostatic hypertrophic cells do not secrete EN2. This review discusses the enormous potential of EN2 to address this unmet need and provide the urologist with a simple, inexpensive, and reliable prostate cancer biomarker.

The role of the prostate cancer gene 3 urine test in addition to serum prostate-specific antigen level in prostate cancer screening among breast cancer, early-onset gene mutation carriers

OBJECTIVE

To evaluate the additive value of the prostate cancer gene 3 (PCA3) urine test to serum prostate-specific antigen (PSA) in prostate cancer (PC) screening among breast cancer, early-onset gene (BRCA) mutation carriers. This study was performed among the Dutch participants of IMPACT, a large international study on the effectiveness of PSA screening among BRCA mutation carriers.

MATERIALS AND METHODS

Urinary PCA3 was measured in 191 BRCA1 mutation carriers, 75 BRCA2 mutation carriers, and 308 noncarriers. The physicians and participants were blinded for the results. Serum PSA level ≥ 3.0 ng/ml was used to indicate prostate biopsies. PCA3 was evaluated (1) as an independent indicator for prostate b iopsies and (2) as an indicator for prostate biopsies among men with an elevated PSA level. PC detected up to the 2-year screening was used as gold standard as end-of-study biopsies were not performed.

RESULTS

Overall, 23 PCs were diagnosed, 20 of which were in men who had an elevated PSA level in the initial screening round. (1) PCA3, successfully determined in 552 participants, was elevated in 188 (cutoff ≥ 25; 34%) or 134 (cutoff ≥ 35; 24%) participants, including 2 of the 3 PCs missed by PSA. PCA3 would have added 157 (≥ 25; 28%) or 109 (≥ 35; 20%) biopsy sessions to screening with PSA only. (2) Elevated PCA3 as a requirement for biopsies in addition to PSA would have saved 37 (cutoff ≥ 25) or 43 (cutoff ≥ 35) of the 68 biopsy sessions, and 7 or 11 PCs would have been missed, respectively, including multiple high-risk PCs. So far, PCA3 performed best among BRCA2 mutation carriers, but the numbers are still small. Because PCA3 was not used to indicate prostate biopsies, its true diagnostic value cannot be calculated.

CONCLUSIONS

The results do not provide evidence for PCA3 as a useful additional indicator of prostate biopsies in BRCA mutation carriers, as many participants had an elevated PCA3 in the absence of PC. This must be interpreted with caution because PCA3 was not used to indicate biopsies. Many participants diagnosed with PC had low PCA3, making it invalid as a restrictive marker for prostate biopsies in men with elevated PSA levels.

Prostate cancer screening characteristics in men with BRCA1/2 mutations attending a high-risk prevention clinic

INTRODUCTION

The prostate-specific antigen (PSA) era and resultant early detection of prostate cancer has presented clinicians with the challenge of distinguishing indolent from aggressive tumours. Mutations in the BRCA1/2 genes have been associated with prostate cancer risk and prognosis. We describe the prostate cancer screening characteristics of BRCA1/2 mutation carriers, who may be classified as genetically-defined high risk, as compared to another high-risk cohort of men with a family history of prostate cancer to evaluate the utility of a targeted screening approach for these men.

METHODS

We reviewed patient demographics, clinical screening characteristics, pathological features, and treatment outcomes between a group of BRCA1 or BRCA2 mutation carriers and age-matched men with a family history of prostate cancer followed at our institutional Prostate Cancer Prevention Clinic from 1995 to 2012.

RESULTS

Screening characteristics were similar between the mutation carriers (n = 53) and the family history group (n = 53). Some cancers would be missed in both groups by using a PSA cut-off of >4 ug/L. While cancer detection was higher in the family history group (21% vs. 15%), the mutation carrier group was more likely to have intermediate- or high-risk disease (88% vs. 36%). BRCA2 mutation carriers were more likely to have aggressive disease, biological recurrence, and distant metastasis.

CONCLUSIONS

In our cohort, regular screening appears justified for detecting prostate cancer in BRCA1 and BRCA2 carriers and other high-risk populations. Lowering PSA cut-offs and defining monitoring of PSA velocity as part of the screening protocol may be useful. BRCA2 is associated with more aggressive disease, while the outcome for BRCA1 mutation carriers requires further study. Large multinational studies will be important to define screening techniques for this unique high-risk population.

A practice guideline from the American College of Medical Genetics and Genomics and the National Society of Genetic Counselors: referral indications for cancer predisposition assessment

DISCLAIMER

The practice guidelines of the American College of Medical Genetics and Genomics (ACMG) and the National Society of Genetic Counselors (NSGC) are developed by members of the ACMG and NSGC to assist medical geneticists, genetic counselors, and other health-care providers in making decisions about appropriate management of genetic concerns, including access to and/or delivery of services. Each practice guideline focuses on a clinical or practice-based issue and is the result of a review and analysis of current professional literature believed to be reliable. As such, information and recommendations within the ACMG and NSGC joint practice guidelines reflect the current scientific and clinical knowledge at the time of publication, are current only as of their publication date, and are subject to change without notice as advances emerge. In addition, variations in practice, which take into account the needs of the individual patient and the resources and limitations unique to the institution or type of practice, may warrant approaches, treatments, and/or procedures that differ from the recommendations outlined in this guideline. Therefore, these recommendations should not be construed as dictating an exclusive course of management, nor does the use of such recommendations guarantee a particular outcome. Genetic counseling practice guidelines are never intended to displace a health-care provider's best medical judgment based on the clinical circumstances of a particular patient or patient population. Practice guidelines are published by the ACMG or the NSGC for educational and informational purposes only, and neither the ACMG nor the NSGC "approve" or "endorse" any specific methods, practices, or sources of information.Cancer genetic consultation is an important aspect of the care of individuals at increased risk of a hereditary cancer syndrome. Yet several patient, clinician, and system-level barriers hinder identification of individuals appropriate for cancer genetics referral. Thus, the purpose of this practice guideline is to present a single set of comprehensive personal and family history criteria to facilitate identification and maximize appropriate referral of at-risk individuals for cancer genetic consultation. To develop this guideline, a literature search for hereditary cancer susceptibility syndromes was conducted using PubMed. In addition, GeneReviews and the National Comprehensive Cancer Network guidelines were reviewed when applicable. When conflicting guidelines were identified, the evidence was ranked as follows: position papers from national and professional organizations ranked highest, followed by consortium guidelines, and then peer-reviewed publications from single institutions. The criteria for cancer genetic consultation referral are provided in two formats: (i) tables that list the tumor type along with the criteria that, if met, would warrant a referral for a cancer genetic consultation and (ii) an alphabetical list of the syndromes, including a brief summary of each and the rationale for the referral criteria that were selected. Consider referral for a cancer genetic consultation if your patient or any of their first-degree relatives meet any of these referral criteria.

Subgroups of familial and aggressive prostate cancer with considerable frequencies of BRCA2 mutations

BACKGROUND

One of the known risk factors for prostate cancer (PrCa) is germline mutations in the BRCA2 gene. Previous searches for clinical characteristics which could identify a subgroup of patients enriched for mutation carriers revealed early onset and aggressive PrCa as useful parameters, but they are rather unspecific.

METHODS

Identification of BRCA2 mutation carriers by sequencing all exons of BRCA2 in a German cohort of 382 familial PrCa cases and of 92 sporadic PrCa cases with early onset (≤60 years). To define a subgroup of PrCa patients enriched for BRCA2 mutation carriers, we used clinical parameters including a detailed family history (FH) for PrCa and breast cancer.

RESULTS

Five BRCA2 mutations and ten variants of unknown significance (VUS) were identified. While the VUS were evenly distributed among the groups, mutation carriers were lacking from the sporadic cases and over represented among familial cases with aggressive disease. High prostate specific antigen (PSA) at diagnosis (>20 ng/ml) was the only criterion with significant enrichment of mutation carriers (6.4%, P = 0.0005). In men with aggressive disease, death from PrCa (6.3% including FH of lethal PrCa; P = 0.05) and FH of both prostate and breast cancer (4.8%; P = 0.3) increased the frequency of mutation carriers. Larger studies and/or meta-analyses are needed to validate these parameters.

CONCLUSIONS

We have identified three potentially useful criteria, high PSA, death from PrCa (patient or FH), and aggressive PrCa in combination with FH of breast and prostate cancer. If confirmed, they may become useful for the decision which patients may benefit from BRCA2 testing.

Targeted prostate cancer screening in BRCA1 and BRCA2 mutation carriers: results from the initial screening round of the IMPACT study

BACKGROUND

Men with germline breast cancer 1, early onset (BRCA1) or breast cancer 2, early onset (BRCA2) gene mutations have a higher risk of developing prostate cancer (PCa) than noncarriers. IMPACT (Identification of Men with a genetic predisposition to ProstAte Cancer: Targeted screening in BRCA1/2 mutation carriers and controls) is an international consortium of 62 centres in 20 countries evaluating the use of targeted PCa screening in men with BRCA1/2 mutations.

OBJECTIVE

To report the first year's screening results for all men at enrollment in the study.

DESIGN, SETTING AND PARTICIPANTS

We recruited men aged 40-69 yr with germline BRCA1/2 mutations and a control group of men who have tested negative for a pathogenic BRCA1 or BRCA2 mutation known to be present in their families. All men underwent prostate-specific antigen (PSA) testing at enrollment, and those men with PSA >3 ng/ml were offered prostate biopsy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

PSA levels, PCa incidence, and tumour characteristics were evaluated. The Fisher exact test was used to compare the number of PCa cases among groups and the differences among disease types.

RESULTS AND LIMITATIONS

We recruited 2481 men (791 BRCA1 carriers, 531 BRCA1 controls; 731 BRCA2 carriers, 428 BRCA2 controls). A total of 199 men (8%) presented with PSA >3.0 ng/ml, 162 biopsies were performed, and 59 PCas were diagnosed (18 BRCA1 carriers, 10 BRCA1 controls; 24 BRCA2 carriers, 7 BRCA2 controls); 66% of the tumours were classified as intermediate- or high-risk disease. The positive predictive value (PPV) for biopsy using a PSA threshold of 3.0 ng/ml in BRCA2 mutation carriers was 48%-double the PPV reported in population screening studies. A significant difference in detecting intermediate- or high-risk disease was observed in BRCA2 carriers. Ninety-five percent of the men were white, thus the results cannot be generalised to all ethnic groups.

CONCLUSIONS

The IMPACT screening network will be useful for targeted PCa screening studies in men with germline genetic risk variants as they are discovered. These preliminary results support the use of targeted PSA screening based on BRCA genotype and show that this screening yields a high proportion of aggressive disease.

PATIENT SUMMARY

In this report, we demonstrate that germline genetic markers can be used to identify men at higher risk of prostate cancer. Targeting screening at these men resulted in the identification of tumours that were more likely to require treatment.

Dietary lutein modulates growth and survival genes in prostate cancer cells

Lutein is a carotenoid pigment present in fruits and vegetables that has anti-inflammatory and antitumor properties. In this study, we examined the effect of lutein on proliferation and survival-associated genes in prostate cancer (PC-3) cells. We found that in vitro culture of PC-3 cells with lutein induced mild decrease in proliferation that improved in combination treatment with peroxisome proliferator-activated receptor gamma (PPARγ) agonists and other chemotherapeutic agents. Flow cytometry analyses showed that lutein improved drug-induced cell cycle arrest and apoptosis in prostate cancer. Gene array and quantitative reverse transcription-polymerase chain reaction analyses showed that lutein altered the expression of growth and apoptosis-associated biomarker genes in PC-3 cells. These findings highlight that lutein modulates the expression of growth and survival-associated genes in prostate cancer cells.

The impact of a BRCA2 mutation on mortality from screen-detected prostate cancer

Background:

Men with a BRCA2 mutation face an increased risk of prostate cancer. These cancers tend to have an aggressive nature and it has not yet been demonstrated that regular screening of BRCA2 carriers is associated with improved survival.

Methods:

We identified 4187 men who underwent a prostate cancer biopsy for an elevated PSA or an abnormal digital rectal examination between 1998 and 2010. We screened the BRCA2 gene in its entirety for mutations and we followed the men for death from prostate cancer until December 2012.

Results:

The 12-year prostate cancer-specific survival rate was 94.3% for men without a BRCA2 mutation and was 61.8% for men with a mutation (P<10⁻⁴; log-rank test).

Conclusions:

The survival of men with screen-detected prostate cancer and a BRCA2 mutation is much poorer than expected.

Interest of individuals from BRCA families to participate in research studies focused on male BRCA carriers

Although men and women are equally likely to carry a mutation in the BRCA1 and BRCA2 (BRCA) genes, the clinical significance of mutations in men remains incompletely defined. We sought evaluate interest of individuals from BRCA families to participate in a research study focused on men from BRCA families. Through an anonymous survey posted on the website of the BRCA patient advocacy organization, facing our risk of cancer empowered (FORCE), data was collected over a 21 month period (August 2010-June 2012) from members of BRCA families. The survey was completed by 405 individuals with known BRCA mutations, including 150 males and 232 females. The median age of survey respondents was 49 years (50 years for males and 48 years for females). Overall, 84% of survey respondents indicated prior BRCA mutation testing (95.2% females, 67.3% males). For the overall group of survey respondents, 84% (86% females, 84% males) indicated they would tell their male relatives about a research study focused on high risk men from BRCA families, and 53% (39% females, 74% males) thought that their male relatives would be interested in participating in such a study. Despite limited studies focused on men from BRCA mutation positive families, our survey suggests that both male and female family members are highly interested in focused on male BRCA mutation carriers. The importance of further studying this topic is underscored by emerging literature that suggest cancer surveillance and treatment decisions may improve outcomes in men with BRCA mutations.

EN2: a novel prostate cancer biomarker

Extensive efforts to identify a clinically useful biomarker for the diagnosis of prostate cancer have resulted in important insights into the biology of the disease, but no new test has been approved by regulatory authorities. The unmet need has also shifted to identifying biomarkers that not only diagnose prostate cancer but also indicate whether the patient has 'significant' disease. EN2 is a homeobox-containing transcription factor secreted specifically by prostate cancers into urine, where it can be detected by a simple ELISA assay. A number of studies have demonstrated the enormous potential of EN2 to address this unmet need and provide the urologist with a simple, cheap and efficient prostate cancer biomarker.

The genetic epidemiology of prostate cancer and its clinical implications

Worldwide, familial and epidemiological studies have generated considerable evidence of an inherited component to prostate cancer. Indeed, rare highly penetrant genetic mutations have been implicated. Genome-wide association studies (GWAS) have also identified 76 susceptibility loci associated with prostate cancer risk, which occur commonly but are of low penetrance. However, these mutations interact multiplicatively, which can result in substantially increased risk. Currently, approximately 30% of the familial risk is due to such variants. Evaluating the functional aspects of these variants would contribute to our understanding of prostate cancer aetiology and would enable population risk stratification for screening. Furthermore, understanding the genetic risks of prostate cancer might inform predictions of treatment responses and toxicities, with the goal of personalized therapy. However, risk modelling and clinical translational research are needed before we can translate risk profiles generated from these variants into use in the clinical setting for targeted screening and treatment.

Predicting high risk disease using serum and DNA biomarkers

PURPOSE OF REVIEW

To explore several serum and genetic-based biomarkers that may prove useful in following men being managed with active surveillance for localized prostate cancer by predicting those that either have the potential to develop, or already harbor occult high grade disease.

RECENT FINDINGS

There is increasing evidence that serum biomarkers human Kallikrein 2, early prostate cancer antigen, urokinase-type plasminogen activator/urokinase-type plasminogen activator receptor, transforming growth factor-β1 and interleukin-6/interleukin-6 receptor and genetic biomarkers BRCA1 and BRCA2, Phosphatase and tensin homolog, cellular myelocytomatosis oncogene and NKX3.1 may predict for aggressive high grade disease and are identifiable early in prostate carcinogenesis.

SUMMARY

One of the barriers of widespread adoption of active surveillance for low risk, localized prostate cancer is the concern that some patients may harbor occult high-risk disease at diagnosis, or develop more aggressive/noncurable disease not detected by our current well established prognostic factors. This review examines several serum and genetic-based biomarkers that appear to be of value in localized prostate cancer, unlike the vast majority of more established prostate cancer biomarkers that have been validated in far more advanced disease. Although the biomarkers discussed show exciting promise, their clinical utility is unknown, and their role in the active surveillance scenario needs further study.

The presence of prostate cancer at biopsy is predicted by a number of genetic variants

Several single nucleotide polymorphisms (SNPs) have been associated with an elevated risk of prostate cancer risk. It is not established if they are useful in predicting the presence of prostate cancer at biopsy or if they can be used to define a low-risk group of men. In this study, 4,548 men underwent a prostate biopsy because of an elevated prostate specific antigen (PSA; ≥4 ng/mL) or an abnormal digital rectal examination (DRE). All men were genotyped for 11 selected SNPs. The effect of each SNP, alone and in combination, on prostate cancer prevalence was studied. Of 4,548 men: 1,834 (40.3%) were found to have cancer. A positive association with prostate cancer was seen for 5 of 11 SNPs studied (rs1800629, rs1859962, rs1447295, rs4430796, rs11228565). The cancer detection rate rose with the number of SNP risk alleles from 29% for men with no variant to 63% for men who carried seven or more risk alleles (OR = 4.2; p = 0.002). The SNP data did not improve the predictive power of clinical factors (age, PSA and DRE) for detecting prostate cancer (AUC: 0.726 vs. 0.735; p = 0.4). We were unable to define a group of men with a sufficiently low prevalence of prostate cancer that a biopsy might have been avoided. In conclusion, our data do not support the routine use of SNP polymorphisms as an adjunct test to be used on the context of prostate biopsy for Polish men with an abnormal screening test.

A personalised approach to prostate cancer screening based on genotyping of risk founder alleles

Background:

To evaluate whether genotyping for 18 prostate cancer founder variants is helpful in identifying high-risk individuals and for determining optimal screening regimens.

Methods:

A serum PSA level was measured and a digital rectal examination (DRE) was performed on 2907 unaffected men aged 40–90. Three hundred and twenty-three men with an elevated PSA (⩾4 ng ml⁻¹) or an abnormal DRE underwent a prostate biopsy. All men were genotyped for three founder alleles in BRCA1 (5382insC, 4153delA and C61G), for four alleles in CHEK2 (1100delC, IVS2+1G>A, del5395 and I157T), for one allele in NBS1 (657del5), for one allele in HOXB13 (G84E), and for nine low-risk single-nucleotide polymorphisms (SNPs).

Results:

On the basis of an elevated PSA or an abnormal DRE, prostate cancer was diagnosed in 135 of 2907 men (4.6%). In men with a CHEK2 missense mutation I157T, the cancer detection rate among men with an elevated PSA or an abnormal DRE was much higher (10.2%, P=0.0008). The cancer detection rate rose with the number of SNP risk genotypes observed from 1.2% for men with no variant to 8.6% for men who carried six or more variants (P=0.04). No single variant was helpful on its own in predicting the presence of prostate cancer, however, the combination of all rare mutations and SNPs improved predictive power (area under the curve=0.59; P=0.03).

Conclusion:

These results suggest that testing for germline CHEK2 mutations improves the ability to predict the presence of prostate cancer in screened men, however, the clinical utility of incorporating DNA variants in the screening process is marginal.

Germline BRCA mutations are associated with higher risk of nodal involvement, distant metastasis, and poor survival outcomes in prostate cancer

PURPOSE

To analyze the baseline clinicopathologic characteristics of prostate tumors with germline BRCA1 and BRCA2 (BRCA1/2) mutations and the prognostic value of those mutations on prostate cancer (PCa) outcomes.

PATIENTS AND METHODS

This study analyzed the tumor features and outcomes of 2,019 patients with PCa (18 BRCA1 carriers, 61 BRCA2 carriers, and 1,940 noncarriers). The Kaplan-Meier method and Cox regression analysis were used to evaluate the associations between BRCA1/2 status and other PCa prognostic factors with overall survival (OS), cause-specific OS (CSS), CSS in localized PCa (CSS_M0), metastasis-free survival (MFS), and CSS from metastasis (CSS_M1).

RESULTS

PCa with germline BRCA1/2 mutations were more frequently associated with Gleason ≥ 8 (P = .00003), T3/T4 stage (P = .003), nodal involvement (P = .00005), and metastases at diagnosis (P = .005) than PCa in noncarriers. CSS was significantly longer in noncarriers than in carriers (15.7 v 8.6 years, multivariable analyses [MVA] P = .015; hazard ratio [HR] = 1.8). For localized PCa, 5-year CSS and MFS were significantly higher in noncarriers (96% v 82%; MVA P = .01; HR = 2.6%; and 93% v 77%; MVA P = .009; HR = 2.7, respectively). Subgroup analyses confirmed the poor outcomes in BRCA2 patients, whereas the role of BRCA1 was not well defined due to the limited size and follow-up in this subgroup.

CONCLUSION

Our results confirm that BRCA1/2 mutations confer a more aggressive PCa phenotype with a higher probability of nodal involvement and distant metastasis. BRCA mutations are associated with poor survival outcomes and this should be considered for tailoring clinical management of these patients.

Prostate cancer and osteoporosis

Adenocarcinoma of the prostate is one of the commonest cancers in the world. Due to a combination of earlier detection and better treatments, survival has increased dramatically. Prostate cancer itself is associated with lower bone density and increased fractures. This is compounded by the use of androgen deprivation therapy, which causes dramatic falls in circulating testosterone and estrogen, resulting in rapid falls in bone density, decreased muscle mass, and increased fracture rates. Bisphosphonates have been demonstrated to prevent and reverse this bone loss, but there are no anti-fracture data. Denosumab, a monoclonal antibody to RANKL, has recently been shown to increase bone density and reduce fracture rates. Prostate cancer also commonly metastasizes to bone where it can cause complications such as fracture and pain. Both zoledronic acid and denosumab have been demonstrated to reduce skeletal related events. Comparative studies would suggest that densosumab may have an advantage over zoledronic acid.

Association between single nucleotide polymorphisms on chromosome 17q and the risk of prostate cancer in a Chinese population

In European populations, 7 single nucleotide polymorphisms (SNPs) on chromosome 17q, 3 SNPs on 17q12, and 4 SNPs on 17q24.3 were recently identified to be closely related to the risk of prostate cancer by a genome-wide association study. In Japanese populations, the correlation between 2 SNPs on 17q and the risk of prostate cancer and tumor aggressiveness was also confirmed by a large-scale experiment. However, whether 17q is associated with prostate cancer and its clinical manifestations in Chinese populations is still unknown. Therefore, we conducted a case-control study in a northern Chinese population and tested 2 SNPs, rs4430796 and rs1859962, on 17q in 124 prostate cancer patients and 111 controls using polymerase chain reaction-high resolution melting curve (PCR-HRM) combined with sequencing. We analyzed the association of the 2 SNPs with the risk of prostate cancer as well as patients' lifestyles, onset ages, Gleason scores, PSA levels, and pathologic stages. We found a significant difference in the G allele of SNP rs1859962 (P = 0.035, OR = 1.51, 95% CI = 1.03-2.21) but not in the rs4430796 genotype frequency or allele frequency distribution between prostate cancer patients and the controls (P > 0.05). Neither of the SNPs was significantly associated with the onset age, Gleason score, PSA level, pathologic stage, or other clinical indicators of patients with prostate cancer (P > 0.05). Our results show that polymorphism of the G allele of SNP rs1859962 is associated with the risk of prostate cancer in a Chinese population.

Familial prostate cancer: the damage done and lessons learnt

BACKGROUND

A 51-year-old French Canadian man presented to his family physician owing to an extensive family history of prostate cancer in five brothers, his father and two paternal uncles. His serum PSA level was 4.9 ng/ml and a six-core biopsy revealed the presence of a prostate adenocarcinoma with a Gleason score of 7 (3+4). He was treated with radical prostatectomy. Repeat PSA tests revealed a gradual rise in PSA levels despite androgen deprivation therapy with bicalutamide and goserelin over the course of 3 years. Genetic evaluation was undertaken in view of his personal and family history. The proband died at the age of 58 years of widespread metastasis.

INVESTIGATIONS

PSA testing, six-core biopsy, genetic counselling and mutation analysis for French Canadian founder mutations in the BRCA1 and BRCA2 genes, histopathological review of tumour tissue from family members, examination of loss of heterozygosity at the BRCA2 gene locus, immunohistochemistry to determine the expression of the ERG nuclear oncoprotein in prostate tumours, genotyping with eight selected risk-associated single nucleotide polymorphisms, Doppler ultrasonography of the leg, CT of the abdomen and pelvis with intravenous and oral contrast, chest CT with intravenous contrast for the assessment of metastatic prostate cancer, genetic testing for the G84E variant in the HOXB13 gene.

DIAGNOSIS

Early-onset and aggressive prostate cancer associated with a nonsense French Canadian BRCA2 founder mutation, c.5857G>T (p.Glu1953(*)).

MANAGEMENT

Radical prostatectomy, hormone therapy with bicalutamide and goserelin, palliative chemotherapy initially with docetaxel plus prednisone then with mitoxantrone plus prednisone, as well as genetic counselling and testing for the proband and his family members.

Role of Engrailed-2 (EN2) as a prostate cancer detection biomarker in genetically high risk men

Controversy surrounds the use of PSA as a biomarker for prostate cancer detection, leaving an unmet need for a novel biomarker in this setting; urinary EN2 may identify individuals with clinically relevant prostate cancer. Male BRCA1 and BRCA2 mutation carriers are at increased risk of clinically significant prostate cancer and may benefit from screening. Urine samples from 413 BRCA1 and BRCA2 mutation carriers and controls were evaluated. Subjects underwent annual PSA screening with diagnostic biopsy triggered by PSA > 3.0 ng/ml; 21 men were diagnosed with prostate cancer. Urinary EN2 levels were measured by ELISA and had a sensitivity of 66.7% and specificity of 89.3% for cancer detection. There was no statistically significant difference in EN2 levels according to genetic status or Gleason score. Urinary EN2 may be useful as a non-invasive early biomarker for prostate cancer detection in genetically high-risk individuals.

Identification of potential complementary serum biomarkers to differentiate prostate cancer from benign prostatic hyperplasia using gel- and lectin-based proteomics analyses

Diagnosis of prostate cancer (PCa) is currently much reliant on the invasive and time-consuming transrectal ultrasound-guided biopsy of the prostate gland, particularly in light of the inefficient use of prostate-specific antigen as its biomarker. In the present study, we have profiled the sera of patients with PCa and benign prostatic hyperplasia (BPH) using the gel- and lectin-based proteomics methods and demonstrated the significant differential expression of apolipoprotein AII, complement C3 beta chain fragment, inter-alpha-trypsin inhibitor heavy chain 4 fragment, transthyretin, alpha-1-antitrypsin, and high molecular weight kininogen (light chain) between the two groups of patients' samples. Our data are suggestive of the potential use of the serum proteins as complementary biomarkers to effectively discriminate PCa from BPH, although this requires further extensive validation on clinically representative populations.

Identifying and exploiting defects in the Fanconi anemia/BRCA pathway in oncology

Defects in components of DNA repair pathways are responsible for numerous hereditary cancer syndromes and are also common in many sporadic malignancies. Inherited mutations in the breast cancer susceptibility genes BRCA1 and BRCA2 or components of the Fanconi anemia (FA) complex incite genomic instability and predispose to malignancy. The products of the BRCA and FA genes participate in a conserved DNA damage repair pathway that is responsible for repairing interstrand crosslinks and double-strand DNA breaks by homologous recombination. While the genetic instability resulting from FA/BRCA dysfunction contributes to cancer pathogenesis, deficiency of these genes also lends to therapeutic exploitation. Crosslinking agents and ionizing radiation induce damage in cancer cells that requires the FA/BRCA pathway to be resolved; thus cancers that are deficient in BRCA1, BRCA2, or any other component of the FA/BRCA pathway are hypersensitive to these agents. Moreover, emerging synthetic lethal strategies offer opportunities to selectively target cancer cells with defects in homologous recombination. Conversely, enhanced activity of the FA/BRCA pathway is responsible for acquired resistance to specific therapeutic agents, suggesting that both dysfunction and hyperfunction of the FA/BRCA repair machinery are rational targets for cancer therapy. Selection of specific cytotoxic agents based on repair capacity may improve responses and enable personalized cytotoxic chemotherapy. This article reviews the FA/BRCA pathway and current approaches to identify deficiencies within it, discusses synthetic lethality and enhanced repair capacity as causes of therapeutic hypersensitivity and resistance, respectively, and highlights recent studies that have linked FA/BRCA pathway function with therapeutic efficacy.

The role of BRCA1 and BRCA2 in prostate cancer

One of the strongest risk factors for prostate cancer is a family history of the disease. Germline mutations in the breast cancer predisposition gene 2 (BRCA2) are the genetic events known to date that confer the highest risk of prostate cancer (8.6-fold in men ≤65 years). Although the role of BRCA2 and BRCA1 in prostate tumorigenesis remains unrevealed, deleterious mutations in both genes have been associated with more aggressive disease and poor clinical outcomes. The increasing incidence of prostate cancer worldwide supports the need for new methods to predict outcome and identify patients with potentially lethal forms of the disease. As we present here, BRCA germline mutations, mainly in the BRCA2 gene, are one of those predictive factors. We will also discuss the implications of these mutations in the management of prostate cancer and hypothesize on the potential for the development of strategies for sporadic cases with similar characteristics.

Sapacitabine for cancer

INTRODUCTION

Sapacitabine is an orally bioavailable nucleoside analog prodrug that is in clinical trials for hematologic malignancies and solid tumors. The active metabolite of sapacitabine, CNDAC (2'-C-cyano-2'-deoxy-1-β-D-arabino-pentofuranosylcytosine), exhibits the unique mechanism of action of causing single-strand breaks (SSBs) after incorporation into DNA, which are converted into double-strand breaks (DSBs) when cells enter a second S-phase. CNDAC-induced DSBs are predominantly repaired through homologous recombination (HR). Cells deficient in HR components are greatly sensitized to CNDAC. Therefore, sapacitabine could be specifically effective against tumors that are deficient in this repair pathway.

AREAS COVERED

This review summarizes results from supporting evidence for the mechanisms of action of sapacitabine, its preclinical activities and the current results of clinical trials in a variety of cancers. The novel action mechanism of sapacitabine is discussed, with a view to validate it as a chemotherapeutic drug targeting malignancies with defects in HR.

EXPERT OPINION

Knowledge of CNDAC mechanism identifies tumors that may be sensitized to sapacitabine, thus enabling a personalized treatment strategy. It also creates the opportunity to overcome resistance to current front-line therapies and identify synergistic interactions with known anticancer drugs. The results of such investigations may provide rationales for the design of sapacitabine-based clinical trials.

Cancer worry among Norwegian male BRCA1/2 mutation carriers

This qualitative study explored the experiences of Norwegian men after being identified as BRCA 1/2 mutation-positive. Only limited knowledge is available on this topic; therefore, the aim of this study was to gain a deeper insight from the men's own perspectives. Data were collected from in-depth interviews with 15 men and seven of their partners. The participants described fear of cancer development, and two main narrative patterns were identified: fear for their own health, including fear of developing cancer, and negative feelings about responsibility for others' health. The men expressed fear of developing cancer themselves and described a need for genetic risk information. They were also deeply concerned about how the mutation might affect their children and other relatives. There is a need for guidelines concerning genetic risk information and follow-up programs for male BRCA 1/2 mutation carriers. This study adds valuable contextual insights into their experiences of living with fear of cancer.

Decreased prostate cancer-specific survival of men with BRCA2 mutations from multiple breast cancer families

The role of a germ-line BRCA2 mutation in the development of prostate cancer is established, but the clinical presentation linked to outcome for this group of men has not been well described. A total of 148 men from 1,423 families were ascertained from the kConFab consortium. Each participant met the following criteria: (i) a verified case of prostate cancer; (ii) confirmed as either a carrier or noncarrier of a family-specific BRCA pathogenic mutation; (iii) comprehensive clinical and treatment data were available. Clinical data were linked to treatment received and overall survival was analyzed by Kaplan-Meier. Prostate cancer in men from breast cancer-prone families has a high risk of disease progression, irrespective of mutation status. BRCA2 mutation carriers have an increased risk of death and prostate cancer-related death [HR (95% CI) 4.5 (2.12-9.52), P = 8.9 × 10(-5)] by comparison with noncarriers. Serum PSA readings taken prior to diagnosis in 90% of all men, age adjusted, were above clinical significance. Following D'Amico risk stratification, 77.5% of BRCA2 mutation carriers and 58.7% of noncarriers had high-risk disease. BRCA2 mutation status was also an independent prognostic indicator of overall survival. Furthermore, there was a poor overall survival outcome for both the BRCA2 mutation carriers and noncarriers given curative-intent treatment. All men in breast cancer-prone families are at risk of developing aggressive prostate cancer. This information is significant and should be included in discussions with genetic counselors and medical professionals when discussing prostate cancer treatment options for men in these families, irrespective of mutation status.

Skp2: a novel potential therapeutic target for prostate cancer

Prostate cancer is the most frequently diagnosed tumor in men and the second most common cause of cancer-related death for males in the United States. It has been shown that multiple signaling pathways are involved in the pathogenesis of prostate cancer, such as androgen receptor (AR), Akt, Wnt, Hedgehog (Hh) and Notch. Recently, burgeoning amounts of evidence have implicated that the F-box protein Skp2 (S-phase kinase associated protein 2), a well-characterized oncoprotein, also plays a critical role in the development and progression of prostate cancer. Therefore, this review discusses the recent literature regarding the function and regulation of Skp2 in the pathogenesis of prostate cancer. Furthermore, we highlight that Skp2 may represent an attractive therapeutic target, thus warrants further development of agents to target Skp2, which could have significant therapeutic impact on prostate cancer.

Extending the scope of diagnostic chromosome analysis: detection of single gene defects using high-resolution SNP microarrays

Microarray analysis has provided significant advances in the diagnosis of conditions resulting from submicroscopic chromosome abnormalities. It has been recommended that array testing should be a "first tier" test in the evaluation of individuals with intellectual disability, developmental delay, congenital anomalies, and autism. The availability of arrays with increasingly high probe coverage and resolution has increased the detection of decreasingly small copy number changes (CNCs) down to the intragenic or even exon level. Importantly, arrays that genotype SNPs also detect extended regions of homozygosity. We describe 14 examples of single gene disorders caused by intragenic changes from a consecutive set of 6,500 tests using high-resolution SNP microarrays. These cases illustrate the increased scope of cytogenetic testing beyond dominant chromosome rearrangements that typically contain many genes. Nine of the cases confirmed the clinical diagnosis, that is, followed a "phenotype to genotype" approach. Five were diagnosed by the laboratory analysis in the absence of a specific clinical diagnosis, that is, followed a "genotype to phenotype" approach. Two were clinically significant, incidental findings. The importance of astute clinical assessment and laboratory-clinician consultation is emphasized to optimize the value of microarrays in the diagnosis of disorders caused by single gene copy number and sequence mutations.

Skp2 overexpression is associated with loss of BRCA2 protein in human prostate cancer

BRCA2 (breast cancer 2, early onset) is a tumor suppressor gene that confers increased susceptibility for prostate cancer (PCa). Previous in vitro experiments demonstrated that Skp2, an E3 ubiquitin ligase aberrantly overexpressed in PCa, is involved in the proteolytic degradation of BRCA2 in PCa cells, suggesting that the BRCA2-Skp2 interaction may play a role in prostate tumorigenesis. Herein, we investigated BRCA2 and Skp2 expression during PCa development using a prostate TMA. Although luminal and basal benign prostate epithelium exhibited moderate to strong nuclear BRCA2 immunostaining, the intensity and number of positive nuclei decreased significantly in high-grade prostatic intraepithelial neoplasia and PCa. Decreased frequency and intensity of nuclear BRCA2 labeling were inversely correlated with Skp2 expression in high-grade prostatic intraepithelial neoplasia and PCa. To functionally assess the effects of BRCA2 and Skp2 expression on prostate malignant transformation, we overexpressed Skp2 in normal immortalized prostate cells. Skp2 overexpression reduced BRCA2 protein and promoted cell growth and migration. A similar phenotype was observed after reduction of BRCA2 protein levels using specific BRCA2 small-interfering RNA. Forced BRCA2 expression in Skp2-overexpressing stable transfectants inhibited the migratory and growth properties by >60%. These results show that loss of BRCA2 expression during prostate tumor development is strongly correlated with both migratory behavior and cancer growth and include Skp2 as a BRCA2 proteolytic partner in vivo.

A risk prediction algorithm based on family history and common genetic variants: application to prostate cancer with potential clinical impact

Genome wide association studies have identified several single nucleotide polymorphisms (SNPs) that are independently associated with small increments in risk of prostate cancer, opening up the possibility for using such variants in risk prediction. Using segregation analysis of population-based samples of 4,390 families of prostate cancer patients from the UK and Australia, and assuming all familial aggregation has genetic causes, we previously found that the best model for the genetic susceptibility to prostate cancer was a mixed model of inheritance that included both a recessive major gene component and a polygenic component (P) that represents the effect of a large number of genetic variants each of small effect, where . Based on published studies of 26 SNPs that are currently known to be associated with prostate cancer, we have extended our model to incorporate these SNPs by decomposing the polygenic component into two parts: a polygenic component due to the known susceptibility SNPs, , and the residual polygenic component due to the postulated but as yet unknown genetic variants, . The resulting algorithm can be used for predicting the probability of developing prostate cancer in the future based on both SNP profiles and explicit family history information. This approach can be applied to other diseases for which population-based family data and established risk variants exist.

The therapeutic ratio is preserved for radiotherapy or cisplatin treatment in BRCA2-mutated prostate cancers

Prostate cancers in patients with a mutation in BRCA2 have earlier disease onset and an aggressive course, often necessitating the use of systemic therapy. However, these tumours are DNA repair-defective and could respond favourably to Parp inhibitors or DNA-damaging agents, depending on the therapeutic ratio (ratio of tumour response to normal tissue toxicity). We describe 3 patients treated with precision radiotherapy or cisplatin who responded favourably to both agents, yet did not suffer undue toxicity. We review the concept of treating such patients with agents that are selectively toxic to repair-deficient tumours.

Low-dose rate brachytherapy for men with localized prostate cancer

BACKGROUND

Localized prostate cancer is a slow growing tumor for many years for the majority of affected men. Low-dose rate brachytherapy (LDR-BT) is short-distance radiotherapy using low-energy radioactive sources. LDR-BT has been recommended for men with low risk localized prostate cancer.

OBJECTIVES

To assess the benefit and harm of LDR-BT compared to radical prostatectomy (RP), external beam radiotherapy (EBRT), and no primary therapy (NPT) in men with localized prostatic cancer.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (from 1950), and EMBASE (from 1980) were searched in June 2010 as well as online trials registers and reference lists of reviews.

SELECTION CRITERIA

Randomized, controlled trials comparing LDR-BT versus RP, EBRT, and NPT in men with clinically localized prostate cancer.

DATA COLLECTION AND ANALYSIS

Data on study methods, participants, treatment regimens, observation period and outcomes were recorded by two reviewers independently.

MAIN RESULTS

We identified only one RCT (N = 200; mean follow up 68 months). This trial compared LDR-BT and RP. The risk of bias was deemed high. Primary outcomes (overall survival, cause-specific mortality, or metastatic-free survival) were not reported. Biochemical recurrence-free survival at 5 years follow up was not significantly different between LDR-BT (78/85 (91.8%)) and RP (81/89 (91.0%)); P = 0.875; relative risk 0.92 (95% CI: 0.35 to 2.42).For severe adverse events reported at 6 months follow up, results favored LDR-BT for urinary incontinence (LDR-BT 0/85 (0.0%) versus RP 16/89 (18.0%); P < 0.001; relative risk 0) and favored RP for urinary irritation (LDR-BT 68/85 (80.0%) versus RP 4/89 (4.5%); P < 0.001; relative risk 17.80, 95% CI 6.79 to 46.66). The occurrence of urinary stricture did not significantly differ between the treatment groups (LDR-BT 2/85 (2.4%) versus RP 6/89 (6.7%); P = 0.221; relative risk 0.35, 95% CI: 0.07 to 1.68). Long-term information was not available.We did not identify significant differences of mean scores between treatment groups for patient-reported outcomes function and bother as well as generic health-related quality of life.

AUTHORS' CONCLUSIONS

Low-dose rate brachytherapy did not reduce biochemical recurrence-free survival versus radical prostatectomy at 5 years. For short-term severe adverse events, low-dose rate brachytherapy was significantly more favorable for urinary incontinence, but radical prostatectomy was significantly more favorable for urinary irritation. Evidence is based on one RCT with high risk of bias.

New insights into the prevention and treatment of familial breast cancer

Individuals who inherit a deleterious mutation in BRCA1 or BRCA2 are at very high risk for breast cancer but there are several strategies available for successfully managing this risk. Breast cancers that develop in the context of germline BRCA gene mutation present challenges for management but also opportunities. DNA damaging agents, like cisplatin, and the new class of drugs called PARP inhibitors exploit the underlying defect in DNA damage repair to great effect.

Targeted prostate cancer screening in men with mutations in BRCA1 and BRCA2 detects aggressive prostate cancer: preliminary analysis of the results of the IMPACT study

OBJECTIVE

To evaluate the role of targeted prostate cancer screening in men with BRCA1 or BRCA2 mutations, an international study, IMPACT (Identification of Men with a genetic predisposition to ProstAte Cancer: Targeted screening in BRCA1/2 mutation carriers and controls), was established. This is the first multicentre screening study targeted at men with a known genetic predisposition to prostate cancer. A preliminary analysis of the data is reported.

PATIENTS AND METHODS

Men aged 40-69 years from families with BRCA1 or BRCA2 mutations were offered annual prostate specific antigen (PSA) testing, and those with PSA > 3 ng/mL, were offered a prostate biopsy. Controls were men age-matched (± 5 years) who were negative for the familial mutation.

RESULTS

In total, 300 men were recruited (205 mutation carriers; 89 BRCA1, 116 BRCA2 and 95 controls) over 33 months. At the baseline screen (year 1), 7.0% (21/300) underwent a prostate biopsy. Prostate cancer was diagnosed in ten individuals, a prevalence of 3.3%. The positive predictive value of PSA screening in this cohort was 47·6% (10/21). One prostate cancer was diagnosed at year 2. Of the 11 prostate cancers diagnosed, nine were in mutation carriers, two in controls, and eight were clinically significant.

CONCLUSIONS

The present study shows that the positive predictive value of PSA screening in BRCA mutation carriers is high and that screening detects clinically significant prostate cancer. These results support the rationale for continued screening in such men.

Cancer biomarker discovery: the entropic hallmark

Background

It is a commonly accepted belief that cancer cells modify their transcriptional state during the progression of the disease. We propose that the progression of cancer cells towards malignant phenotypes can be efficiently tracked using high-throughput technologies that follow the gradual changes observed in the gene expression profiles by employing Shannon's mathematical theory of communication. Methods based on Information Theory can then quantify the divergence of cancer cells' transcriptional profiles from those of normally appearing cells of the originating tissues. The relevance of the proposed methods can be evaluated using microarray datasets available in the public domain but the method is in principle applicable to other high-throughput methods.

Methodology/Principal Findings

Using melanoma and prostate cancer datasets we illustrate how it is possible to employ Shannon Entropy and the Jensen-Shannon divergence to trace the transcriptional changes progression of the disease. We establish how the variations of these two measures correlate with established biomarkers of cancer progression. The Information Theory measures allow us to identify novel biomarkers for both progressive and relatively more sudden transcriptional changes leading to malignant phenotypes. At the same time, the methodology was able to validate a large number of genes and processes that seem to be implicated in the progression of melanoma and prostate cancer.

Conclusions/Significance

We thus present a quantitative guiding rule, a new unifying hallmark of cancer: the cancer cell's transcriptome changes lead to measurable observed transitions of Normalized Shannon Entropy values (as measured by high-througput technologies). At the same time, tumor cells increment their divergence from the normal tissue profile increasing their disorder via creation of states that we might not directly measure. This unifying hallmark allows, via the the Jensen-Shannon divergence, to identify the arrow of time of the processes from the gene expression profiles, and helps to map the phenotypical and molecular hallmarks of specific cancer subtypes. The deep mathematical basis of the approach allows us to suggest that this principle is, hopefully, of general applicability for other diseases.

BRCA1 loss preexisting in small subpopulations of prostate cancer is associated with advanced disease and metastatic spread to lymph nodes and peripheral blood

PURPOSE

A preliminary study performed on a small cohort of multifocal prostate cancer (PCa) detected BRCA1 allelic imbalances among circulating tumor cells (CTC). The present analysis was aimed to elucidate the biological and clinical roles of BRCA1 losses in metastatic spread and tumor progression in PCa patients.

EXPERIMENTAL DESIGN

To map molecular progression in PCa outgrowth, we used fluorescence in situ hybridization analysis of primary tumors and lymph node sections, and CTCs from peripheral blood.

RESULTS

We found that 14% of 133 tested patients carried monoallelic BRCA1 loss in at least one tumor focus. Extended molecular analysis of chr17q revealed that this aberration was often a part of larger cytogenetic rearrangement involving chr17q21 accompanied by allelic imbalance of the tumor suppressor gene PTEN and lack of BRCA1 promoter methylation. The BRCA1 losses correlated with advanced T stage (P < 0.05), invasion to pelvic lymph nodes (P < 0.05), as well as biochemical recurrence (P < 0.01). Their prevalence was twice as high within 62 lymph node metastases (LNM) as in primary tumors (27%, P < 0.01). The analysis of 11 matched primary PCa-LNM pairs confirmed the suspected transmission of genetic abnormalities between these two sites. In four of seven patients with metastatic disease, BRCA1 losses appeared in a minute fraction of cytokeratin- and vimentin-positive CTCs.

CONCLUSIONS

Small subpopulations of PCa cells bearing BRCA1 losses might be one confounding factor initiating tumor dissemination and might provide an early indicator of shortened disease-free survival.

Brca2 and Trp53 deficiency cooperate in the progression of mouse prostate tumourigenesis

Epidemiological studies have shown that one of the strongest risk factors for prostate cancer is a family history of the disease, suggesting that inherited factors play a major role in prostate cancer susceptibility. Germline mutations in BRCA2 predispose to breast and ovarian cancer with its predominant tumour suppressor function thought to be the repair of DNA double-strand breaks. BRCA2 has also been implicated in prostate cancer etiology, but it is unclear the impact that mutations in this gene have on prostate tumourigenesis. Here we have undertaken a genetic analysis in the mouse to determine the role of Brca2 in the adult prostate. We show that deletion of Brca2 specifically in prostate epithelia results in focal hyperplasia and low-grade prostate intraepithelial neoplasia (PIN) in animals over 12 months of age. Simultaneous deletion of Brca2 and the tumour suppressor Trp53 in prostate epithelia gave rise to focal hyperplasia and atypical cells at 6 months, leading to high-grade PIN in animals from 12 months. Epithelial cells in these lesions show an increase in DNA damage and have higher levels of proliferation, but also elevated apoptosis. Castration of Brca2;Trp53 mutant animals led to regression of PIN lesions, but atypical cells persisted that continued to proliferate and express nuclear androgen receptor. This study provides evidence that Brca2 can act as a tumour suppressor in the prostate, and the model we describe should prove useful in the development of new therapeutic approaches.

In Western countries, prostate cancer is the most common male cancer and the second biggest cause of cancer-related deaths in men. Men with a familial history of either breast or ovarian cancer have an elevated predisposition to prostate cancer, suggesting there is a genetic element to this disease. Indeed, the inheritance of a mutated form of the breast cancer susceptibility gene BRCA2 has been linked to the development of prostate cancer, although the precise role that BRCA2 dysfunction plays in the development of prostate cancer is unclear. To address this, we have generated an animal model in which the mouse Brca2 gene is specifically deleted in the adult prostate. These mice develop precancerous prostate lesions, which progress in severity and incidence with the loss-of-function of an additional tumour suppressor, Trp53. Importantly, blocking male steroidal hormone production by castration leads to partial regression of the prostate lesions, however cells continue to proliferate after androgen withdrawal. This suggests human BRCA2 mutant prostate tumours, like the majority of prostate cancers, will respond to hormone therapy, but will relapse, as frequently occurs in this disease. In summary, our model suggests that BRCA2 acts as a tumour suppressor in the prostate and provides a pre-invasive model to test novel therapeutics.